TOUCH. ,349 



bivalve mollusca have, indeed, a set of tentacula 

 placed near the mouth, but they are short, and of 

 little power. It is probable that the foot may also 

 be employed by these animals as an organ of 

 touch. 



Fishes are, in general, very ill-constructed for 

 the exercise of this sense; and their fins are used 

 for no other purposes than those of progressive 

 motion. That part of the surface which possesses 

 the most acute feeling is the under-side, where the 

 integuments are the thinnest. The chief seat of 

 the sense of touch, however, is the lip, or end of 

 the snout, which is largely supplied with nerves ; 

 and perhaps the cirrhi, or little vermiform pro- 

 cesses called barbels, which in some species are 

 appended to the mouth, may be subservient to this 

 sense. These kind of tentacula are remarkable for 

 their length and mobility in the Lophius piscalorius, 

 or Angler; and it is said that they are employed by 

 the fish, while lurking in ambush, as a decoy to 

 other fishes, which they entice by their resem- 

 blance to worms. These processes in the Silunis 

 giauis are moved by particular muscles. 



Serpents, from the great flexibility of their spine, 

 are capable of grasping and twining round objects 

 of almost any shape, and of taking, as it were, 

 their exact measure. This conformation must be 

 exceedingly favourable to the acquisition of correct 

 perceptions of touch. As it is these perceptions, 

 which, as we shall afterwards find, lay the founda- 

 tion of the most perfect acquaintance with the tan- 

 gible properties of surrounding bodies, we may 

 presume tiiat this power contributes much to the 

 sagacity possessed by these animals. It has been 



